batman-adv: retrieve B.A.T.M.A.N. V WiFi neighbor stats from real interface

Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
[sven.eckelmann@open-mesh.com: re-add batadv_get_real_netdev to take rtnl
 semaphore for batadv_get_real_netdevice]
Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/bat_v_elp.c

@@ -75,6 +75,7 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
 {
 	struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 	struct ethtool_link_ksettings link_settings;
+	struct net_device *real_netdev;
 	struct station_info sinfo;
 	u32 throughput;
 	int ret;
@@ -94,8 +95,13 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
 			/* unsupported WiFi driver version */
 			goto default_throughput;
 
-		ret = cfg80211_get_station(hard_iface->net_dev,
-					   neigh->addr, &sinfo);
+		real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
+		if (!real_netdev)
+			goto default_throughput;
+
+		ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
+
+		dev_put(real_netdev);
 		if (ret == -ENOENT) {
 			/* Node is not associated anymore! It would be
 			 * possible to delete this neighbor. For now set

net/batman-adv/hard-interface.c

@@ -206,6 +206,9 @@ static bool batadv_is_valid_iface(const struct net_device *net_dev)
  *  interface on top of another 'real' interface
  * @netdev: the device to check
  *
+ * Callers must hold the rtnl semaphore. You may want batadv_get_real_netdev()
+ * instead of this.
+ *
  * Return: the 'real' net device or the original net device and NULL in case
  *  of an error.
  */
@@ -242,6 +245,25 @@ out:
 	return real_netdev;
 }
 
+/**
+ * batadv_get_real_netdev - check if the given net_device struct is a virtual
+ *  interface on top of another 'real' interface
+ * @net_device: the device to check
+ *
+ * Return: the 'real' net device or the original net device and NULL in case
+ *  of an error.
+ */
+struct net_device *batadv_get_real_netdev(struct net_device *net_device)
+{
+	struct net_device *real_netdev;
+
+	rtnl_lock();
+	real_netdev = batadv_get_real_netdevice(net_device);
+	rtnl_unlock();
+
+	return real_netdev;
+}
+
 /**
  * batadv_is_wext_netdev - check if the given net_device struct is a
  *  wext wifi interface

net/batman-adv/hard-interface.h

@@ -65,6 +65,7 @@ enum batadv_hard_if_cleanup {
 
 extern struct notifier_block batadv_hard_if_notifier;
 
+struct net_device *batadv_get_real_netdev(struct net_device *net_device);
 bool batadv_is_cfg80211_hardif(struct batadv_hard_iface *hard_iface);
 bool batadv_is_wifi_hardif(struct batadv_hard_iface *hard_iface);
 struct batadv_hard_iface*